RJ45 ethernet ports not working after installing Ventura

You haven't told us anything about how and when this problem manifested. Was anything done or changed? To address a problem such as this it is necessary to take a few steps so you can identify whether the problem is in the Mac or elsewhere. I would try the following to see what happens.

• Try turning off the modem and restarting it to reset it.
• Use a different Ethernet cable (and connecters if used) and see if that fixes it. Also recheck your connections.
• Do you have internet access via Wi-Fi? If so, that tells you that the internet and modem is working.
• Try restarting the computer in the Safe Mode. Hold down the Shift key on restart. This can take up to ten minutes while the Mac repairs its OS and empties its caches. See if that works. If so, restart and recheck.

(Please don't write in all caps. It's the online equivalent of shouting.)

Are you saying that in System Settings->Network, Ethernet does not appear?

What is your mac model, and which Ethernet is this? Built-in, or through some adapter or dock, and which one?